Flexible abrasive bands



Oct. 24, 1961 P. c. TUCKER FLEXIBLE ABRASIVE BANDS Filed NOV. 28, 1958rates This invention relates to flexible abrasive bands and isparticularly concerned with abrasive bands formed from strips ofopen-mesh abrasive-coated fabrics that are secured together at theirends.

Flexible abrasive bands, belts, sleeves, and the like (these articlesbeing hereinafter referred to generically as abrasive bands), are inextensive use for wood and metal finishing. Conventional abrasive beltsand the like are formed from strips of abrasive-coated paper or cloth bysecuring the ends of the strips together in suitable fashion such as bythe use of adhesives. Abrasive bands have also been made from open-mesh,abrasive-coated fabrics of the type shown and claimed in U.S. Patent No.2,740,239, the process used being similar to that employed inmanufacturing conventional abrasive belts. In general, the conventionalmethod comprises slitting the wide web of abrasive-coated fabric that isproduced on the coating machine parallel with the length of said web toform strips of the desired width, cutting off the strips at the lengthdesired, removing abrasive from opposite sides of the ends of thestrips, and fastening the ends of the respective strips together byadhesive, with the cleared portions thereof in contact.

It has been found that flexible abrasive belts formed of open-mesh,abrasive-coated fabrics when used in polishing metal often produce afinish which may be described as lined, the metal surface having aplurality of shallow grooves and small ridges alternating across thework piece in a direction normal to the travel of the abrasive belt.This apparently results from the reticular character of such belts andthe consequent concentration of abrasive particles along substantiallycontinuous and parallel longitudinal lines thereon. With abrasive beltsformed from conventional abrasive-coated paper and cloth difiicultieswith lining in polishing metal are not encountered because the particlesof abrasive material are substantially uniformly and randomlydistributed over the surface of the backing. Nevertheless, theadvantages of abrasive belts formed from open-mesh, abrasive-coatedfabrics in coolness of cutting and in economy are so great that it isdesirable to use them.

Accordingly, it is an object of the present invention to provideflexible abrasive bands formed from strips of open-mesh, abrasive-coatedfabric materials secured together at their respective ends, which do notproduce a lined finish in polishing metals.

Another object of the present invention is to provide flexible abrasivebands, formed from strips of open-mesh, abrasive-coated fabric materialssecured together at their respective ends which produce a very smoothsurface in polishing metals.

Other objects and advantages of the present invention will be apparentfrom the following description taken in conjunction with the drawings inwhich:

FIGURE 1 is a fragmentary, plan view of a web of open-mesh,abrasive-coated fabric showing the strips used in making flexibleabrasive bands according to the invention; and

FIGURE 2 is a top plan view of a flexible abrasive belt according to theinvention.

The open-mesh, abrasive-coated fabric material from which flexibleabrasive bands are formed, according to the present invention,preferably comprises an open-mesh base fabric woven from continuousfilament yarns such as amazes. Patented Oct. 24, 196i "lee nylon, rayon,glass and the like. Prior to application of the abrasive coating to theyarns of the open-mesh base fabric the yarns thereof are preferablyimpregnated and/ or coated, While the fabric is still under normaltension on the loorn, with a flexible material such as neoprene latexwhich is thereafter cured before removing the fabric from the loom. Theflexible coating material prevents penetration of the yarns of thefabric by the adhesive or bond that is used for securing the abrasiveparticles thereon and permits the production of very flexible abrasivewebs. In addition the fabric is more durable and useful since the fabricyarns are attached at their points of interlacing and the mesh openingstherein are more uniform.

Any desired type or types of natural or synthetic abrasive material maybe used in forming the abrasive coatings on the yarns of the open-meshfabric and the abrasive material or materials employed may be used inany suitable grit size or combination thereof and as single particles orbonded aggregates of particles. The abrasive granules are secured overthe entire exposed surfaces of the coated fabric yarns by a suitableadhesive. The abrasive coating or deposit on the yarns may vary inthickness. However, the mesh openings of the fabric should not becompletely filled, it being desirable for a substantial portion of eachmesh opening to be left clear and unobstructed. Flexible abrasive bandsmade therefrom are therefore reticular.

Preferably the adhesive for the abrasive granules is relatively hard andinert to prevent softening thereof by the heat produced in grinding orpolishing operations or by the coolants commonly employed in suchoperations. While other bonds or adhesives may be used, heat-setting,phenol-formaldehyde condensation product, liquid resins have been foundto be generally suitable. When cured by heat, such adhesives aresubstantially insoluble in most solvents and are little, if any,affected by moderate temperatures.

The open-mesh base fabric may be of any desired type of weave althoughit has been found desirable in many cases to use multiple yarns ineither the Warp or filling or both. In using multiple yarns two, three,or even more yarns are juxtaposed and may, for weaving purposes, betreated as a single flattened, Wide yarn. Such multiple yarns may beemployed in various weaves. The sizes of the yarns used may vary widelydepending upon the intended use of the product, the strength of theyarns, the intended cloth count of the fabric and the desired size ofmesh openings. The yarns in the warp and filling may be the same ordifferent in size.

More detailed information concerning the manufacture and nature ofopen-mesh, abrasive coated fabric material of the type used in formingabrasive bands according to the present invention is contained in US.Patent No. 2,740,239.

It has now been discovered that the lining hitherto often produced inpolishing metal with abrasive belts formed of strips of open-mesh,abrasive-coated fabric material joined together at their respective endsmay be substantially prevented by cutting the strips from which thebelts are made diagonally at a small angle with respect to the length ofthe abrasive-coated fabric web. This is illustrated in FIGURE 1 in whichthe web 11 of a flexible open-mesh, abrasive-coated fabric material mayhave a plurality of strips 12 cut therefrom on the bias. The strips maybe, as shown, of different widths as required for the desired abrasivebelts.

The strips 12 after cutting may be formed into belts or other types ofbands by splicing or joining the ends in any suitable way. According toa method which is preferred for most purposes the ends of the strip aresquared and a small area at each end, but on opposite sides thereof, isthen cleared of abrasive particles by scraping, buffing or the like. Thecleared ends after being coated with a suitable adhesive are broughttogether in overlapping relation and firmly clamped while the adhesivesets.

In FIGURE 2 there is illustrated, and indicated by the numeral 15, aflexible abrasive belt of the type resulting. The ends of the strip fromwhich the belt 15 was formed are spliced as indicated at 16 and the beltis shown mounted on a pair of pulleys 17. It will be seen that the Warpyarns 18 of the fabric strip forming the belt 15 (that is those yarnsrunning longitudinally of the strip) are at an angle to the edge of thebelt.

The type of adhesive employed for splicing the ends of the abrasivestrips will ordinarily vary with the bond or adhesive used for theabrasive granules since the adhesives should be compatible and thecuring conditions required for the former should not damage the latter.When a phenol-formaldehyde condensation product abrasive bond oradhesive is used, a liquid phenolic resin adhesive is preferred forsplicing and the ends of the strip are clamped while the adhesive is setand cured by heating. There are commercially available a great manysuitable phenolic resin adhesive that cure at temperatures as low as 280F. in a resonable time, and any of these may be employed.

The joints of flexible abrasive bands produced in accordance with thepresent invention may extend across the width of the band normal to thelength thereof as shown in FIGURE 2 or may, if desired, be diagonal.Further, if desired, other suitable and desired configurations forsplices of the types known in the abrasive band art may be used. It is,of course, desirable in forming the joint or splice to have it as thinas possible, thereby to minimize irregular polishing action resultingfrom differences in thickness of the band. If it is desired to preserveas much as possible the open mesh or reticular characteristics of theabrasive coated fabric material from which the strips are cut, themethod and apparatus described in U.S. Patent No. 2,778,169 may beemployed in forming bands from such strips so that the mesh openings ofthe overlapping portions of the splice or joint may be in registry tothe maximum extent possible.

Flexible abrasive bands made in accordance with the present inventionfrom strips of open-mesh, abrasivecoated fabric material are highlyefiective in preventing lining of a metal surface when used forpolishing. It has been found by experimentation that a belt angle of 0.5is sufficient to give satisfactorily smooth finishes with the liningeffect being substantially absent. With coarse abrasive grits somewhatimproved finishes may be obtained with belt angles of 0.75l.0. The beltangle thus expressed is not only the angle of the edge of the strip fromwhich the belt is made with the length of the Web from which it is cut,but is also the angle of the warp yarns in the strip with respect to aline parallel with the length of the strip and the edge of the belt.Somewhat larger belt angles may be employed, but there is generally nonecessity therefor and, indeed, an excessive belt angle is to be avoidedsince the uneven stress on the fabric causes the belts to stretch andwear rapidly. It is, therefore, recommended that the angle not exceed2.5

It will be evident from the foregoing description that there is providedby the present invention a highly desirable improvement in themanufacture of flexible abrasive bands from open-mesh, abrasive-coatedfabric strips.

It will also be recognized that numerous variations and modifications inthe process described and in the improved abrasive belts produced may bemade Without departing from the spirit of the invention. Thus, forexample, short lengths of bias-cut strips may be adhesively spliced,endto-end to form flexible abrasive belts, bands or sleeves inaccordance with the invention. In this connection, it should beconsidered that the difference between a band and a belt is often only amatter of relative size. Accordingly, it is desired that the presentinvention should not be interpreted narrowly but should be construed asbroadly as is permitted by the appended claims.

I claim: l

'1. A flexible, reticular, abrasive band formed from a strip of anabrasive-coated fabric, the ends of said strip being firmly attachedtogether, and having the warp yarns thereof at an angle of from about0.5 to 2.5 with respect to a line parallel with the length of said stripand the edge of said band, said abrasive coated fabric comprising anopen-mesh fabric having abrasive granules adhesively secured over theentire exposed surfaces of the yarns of said fabric but not filling themesh openings of said fabric.

2. A flexible, reticular, abrasive band formed from a strip of anabrasive-coated fabric, the ends of said strip being firmly attachedtogether in overlapping relation and the warp yarns of said strip beingdisposed at an angle of from about 0.5 to 2.5 with respect to a lineparallel with the length of said strip and the edge of said band, saidabrasive coated fabric comprising an open-mesh fabric having abrasivegranules adhesively secured over the entire exposed surfaces of theyarns of said fabric but not filling the mesh openings of said fabric.

3. A flexible, reticular, abrasive band consisting of a strip ofabrasive-coated fabric having the ends thereof ad hesively securedtogether in overlapping relation, the warp yarns of said strip beingdisposed at an angle of from about 0.5 to 25 with respect to a lineparallel with the length of said strip and the edge of said band, saidabrasive coated fabric comprising an open-mesh fabric having abrasivegranules adhesively secured over the entire exposed surfaces of theyarns of said fabric but not filling the mesh openings of said fabric.

Freeman Aug. 15, 1916 Ball Jan. 22, 1957

